Résumé
In olive-oil-producing countries, large amounts of waste material are generated as by-product for which there is no ready use and in some cases may have a negative value because of the cost of disposal. Most of these countries depend on fossil fuels for their energy uses, and olive mill wastes can be used to supplement such energy sources using thermochemical conversion processes such as pyrolysis. However, efficient operation of thermochemical conversion systems requires a thorough understanding of the influence of the composition and thermal properties of these by-products on their behaviour during the conversion process. In this study, the thermal behaviour of two olive mill wastes samples (olive mill solid waste: OMSW, and concentrated olive mill wastewater: COMWW) was examined at different heating rates ranging from 5 to 50 A degrees C min(-1) in inert atmosphere using the technique of thermogravimetric analysis. As the increment of heating rates, the variations of characteristic parameters from the TG-DTG curves were determined. The initial temperature of degradation is higher in OMSW, which present a high amount of cellulose in comparison with COMWW. Three methods were used for the determination of kinetic reaction parameters: Friedman, Ozawa-Flynn-Wall and Vyazovkin methods. The results showed that apparent activation energy obtained for the decomposition of hemicelluloses and cellulose derived from OMSW was given as 150-176 and 210.5-235.7 kJ mol(-1), while for COMWW, the values were 133-145 and 255-275 kJ mol(-1), respectively.